Inflation manifold, method of and apparatus for heading plastic safety pins therein

ABSTRACT

A method of heading a thermoplastic safety pin in a manifold for use with an inflatable article such as a life vest, life raft, and the like. Before operation, a manifold has a capsule containing compressed gas mounted thereon, the manifold being actuated to inflate the inflatable article by pulling a lanyard attached to a lever which thrusts a capsule-piercing pin into the soft metal seal on the capsule. Before the operation of the manifold, the lever is held in locked-inoperative position by a frangible plastic pin which extends through a hole in the lever and aligned holes in the body of the manifold on both sides of a longitudinal slot therein which receives the lever when the latter is in inoperative position. When the operator swings the lever in order to advance the capsule-piercing pin to pierce the seal on the capsule, the plastic pin is broken. In accordance with the method of the invention, after the pin has been mounted in the manifold, the previously unheaded end of the pin is partially melted and compressed so as to flow laterally to form a head thereon. The die which engages the initially unheaded end of the pin is heated to a temperature which markedly exceeds the melting point of the plastic material of which the pin is made. In accordance with the method of the invention, such die is brought forcibly into contact with and is removed from engagement with the initially unheaded end of the pin several times a second, so as to avoid the complete melting of the pin and the sticking of the plastic material to the heated die.

This is a continuation of application Ser. No. 558,244, filed Mar. 14,1975 now abandoned.

This invention relates to a method of making certain parts of aninflation manifold assembly.

Although in its broader aspects the invention is not limited thereto,the invention is illustrated herein in connection with the use of theassembly in a CO₂ inflation manifold for use with an inflatable articlesuch as a life vest, life raft, and the like. In the described assembly,the plastic flange or base, adapted for being heat-sealed to the wall ofan inflatable article, has a central passage therethrough into whichthere extends the sleeve-like body of a check valve, such body beingsealed to the mounting flange and locked against relative rotation withrespect thereto. The combination of valve body and mounting flange issealed to the sleeve portion of an inflation manifold in which the valvebody is mounted. Such general combination of mounting flange, valvebody, and inflation manifold is shown, for example, in Mackal U.S. Pat.No. 3,809,288, issued May 7, 1974. In such prior manifold, the CO₂piercing needle is operated by a lever which is held in inoperativeposition by a fine gauge wire, such wire being broken by the deliberateswinging of the lever by the operator through medium of a lanyardsecured thereto. The application of the wire to the manifold istime-consuming, and the presence of the wire detracts somewhat from thetrim appearance of the manifold. Further, the wire extends beyond theoutline of the manifold, and conceivably can be broken prematurely bybecoming entangled with or abraded by some other member or body.

It is among the objects of the present invention to provide a method ofheading the thermoplastic pin after it has been mounted in the manifoldassembly by inserting it through the aligned holes in the body of themanifold and through the hole in the lever.

The above and further objects and novel features of the invention willmore fully appear from the following description when the same is readin conjunction with the accompanying drawings. It is to be expresslyunderstood, however, that the drawings are for the purpose ofillustration only, and are not intended as a definition of the limits ofthe invention.

In the drawings, wherein like reference characters refer to like partsthroughout the several views:

FIG. 1 is a view in elevation of a manifold according to the presentinvention, an inflatable body on which the manifold is mounted beingshown fragmentarily;

FIG. 2 is a view in plan of the inflation manifold of FIG. 1;

FIG. 3 is a view in elevation on an enlarged scale of an unheadedplastic pin employed making the manifold assembly of the invention;

FIG. 4 is a somewhat schematic view in plan of the apparatus of theinvention for heading the lever-locking pin of the manifold; and

FIG. 5 is a composite schematic view illustrating successive portions ofthe operating cycle of the pin-heading apparatus of FIG. 4.

In FIG. 1 there is shown a manifold and check valve assembly sealinglymounted upon a portion of a panel 10 of an inflatable article. Thesleeve-like main body 11 of the check valve passes through and is sealedto a mounting flange 12 made of elastomeric material which isheat-sealable to the panel 10.

The illustrative inflation manifold is designated generally by thereference character 14. The manifold has a passage 13 extendingtherethrough transverse to the broad extent of the manifold, the passagehaving a flat side on the bottom thereof as it is shown in FIG. 1. Thesleeve-like body 11 of the valve, which has an external configurationcomplementary to the cross-section of the passage, extends through suchpassage and is sealingly held therein by a cap nut screwed onto thethreaded outer end of the body 11, there being suitable washersinterposed, on the one hand, between a flange adjacent the inner end ofthe body 11 and the body of the manifold, and, on the other hand,between the cap nut and the body of the manifold on the other sidethereof.

The embodiment of manifold shown in the drawings has a body 22 generallyin the form of a thick disc having parallel front and rear sides 22, 24,respectively, parallel longitudinally spaced ends 29, 30 and upper andlower surfaces 25, 26, respectively (FIGS. 1 and 2), of oppositelyconvex, part-circular cylindrical shape. At its left-hand end as it isshown in the drawings, the body 22 of the manifold is provided withmeans for threadedly receiving the neck of a CO₂ cartridge 32 andsealing it to the gas-conducting chamber inwardly of the body 22 of themanifold. It is to be understood that the capsule 32 has a sealing discof soft metal spanning its neck, such soft metal seal being adapted tobe pierced when required, whereby to release the gas from the capsule sothat it flows into the chamber through a passage and thence through anexit passage into the longitudinal bore in the valve body 11 through aradial passage therein communicating with the exit passage.

The soft metal seal of the capsule 32 is pierced, when it is desired toinflate the inflatable article, by means including a cam lever in theform of a bell crank lever 40 having an elongated lever arm which liesgenerally horizontal (FIGS. 1 and 2) when the lever is in retracted,inoperative position, and a generally vertical, shorter arm having a cam39 on its lower end. The lever 40 is pivotally mounted upon a transversepivot pin 42 which extends from one side of the manifold body to theother and spans a narrow, longitudinally extending lever-receiving slot49 which extends longitudinally of the body 22 at the top thereof anddownwardly along the right-hand end of the manifold body.

Reciprocably and sealingly mounted in a circular cylindrical bore inbody 22 which forms a prolongation of the chamber therein, there is aneedle plunger the enlarged outer end or head of which is in the form ofa cam follower. The plunger is constantly urged to the right intoengagement with the cam 39 by a coil compression spring (not shown)which acts between the head of the plunger and an annular shoulder atthe left-hand end of the chamber. Coaxial of the plunger and forming apart thereof is a capsule seal-piercing needle, the sharpened left-handend of which is spaced from the seal at the end of the neck of thecapsule 32 when the lever 40 is in its retracted, inoperative position,as shown in FIGS. 1 and 2, in which it lies wholly within alongitudinally extending laterally centrally disposed slot 49.

When it is desired to release the gas from the capsule 32 in order toinflate the inflatable article, the lever 40 is swung clockwise aboutits mounting pivot shaft 42 until the high point of the cam 39 haspassed through the position in which it engages the high point of thecam follower on the end of the head of the needle plunger. This causesthe piercing needle first to be thrust to the left against theopposition of the spring sufficiently to pierce the seal in the neck ofthe capsule 32, the spring thereafter thrusting the plunger to the rightas the high point of its cam follower end travels downwardly on the cam39 on lever 40, thereby to open the hole made in the soft metal seal inthe neck of the capsule 32 by the needle. Such swinging of the lever 40is accomplished by pulling a handle 45 on a lanyard cord 44, which issecured to the outer end of the longer arm of the lever 40, by a crimpedsleeve-like means 46 in the direction to the right in FIG. 1. Thelanyard cord is passed through a hole in the outer end of lever 40, andis folded on itself to form a bight 64, the means 46 being crimped onthe two parallel runs 65 of the cord 44.

The lever 40 is secured in the position of FIGS. 1 and 2 by a headedfrangible plastic pin 52 which extends through a hole 54 in lever 40 andaligned passages 55 in body 22 extending inwardly from oppositelydisposed aligned recesses 51 therein. Such pin 52 prevents the unwantedmovement of the lever 40 in a seal-piercing direction, but may readilybe broken by a deliberate, fairly strong pull exerted upon the handle 45of the lanyard. As shown in FIG. 2, the body 22 of the manifold is alsoprovided at its upper left-hand corner (FIGS. 1 and 2) with a broaderrecess 50 into which the outer free end of the lever 40 protrudes,recess 50 receiving the inner end of the cord fastener 46, therebyallowing such fastener to overlie the portion of the body of the capsule32 adjacent its neck so that it, the lanyard cord, and the handle 45 aregenerally out of the way until needed.

The plastic pin 52 as initially formed, is shown in FIG. 3, where it isdesignated 52'. Pin 52' has a first head 56 which is molded integrallytherewith, and has a shank having portions 57 and 59 of equal diameterpositioned to be received, respectively, within the portions of thepin-receiving hole in body 22 which lie closer to and further from thehead 56 of the pin. Between the shank portions 57 and 59 there is aportion 60 of markedly smaller diameter, portion 60 being disposedspaced from the head 56 a distance so that when the pin is assembled inthe manifold as shown, the portion 60 lies within the hole 54 in thelever 40. The axial length of the head 56 on the pin is somewhat lessthan the depth of the recess 51 in the body 22 of the manifold, and theshank or stem portion 59 of the pin is of such length as to form, whenheaded, a second head 61 (FIG. 2) on the pin, head 61 being of suchaxial length that it lies well within its respective recess 51. As aresult, all parts of the pin 52 lie well within the outline of themanifold defined by its bounding surfaces.

An illustrative embodiment of apparatus for carrying out the method ofthe invention is shown in FIGS. 4 and 5. As there shown, the componentsof the apparatus are mounted upon and secured to a base plate 70. Afirst vertical plate member 71 is secured to the plate member 70intermediate the length of the latter, plate 71 having its lengthdisposed transverse to the length of plate 70. A carriage 72 having abase plate 73 is mounted upon plate 70 through the medium of plate 71,the carriage being reciprocal longitudinally of the plate 70, asdesignated by the double-headed arrow. Carriage 72 is supported upon andguided by two spaced parallel guide rods 74, the left-hand ends of whichare affixed to the plate 71; the right-hand end portions of rods 74 runthrough suitable guides affixed to the carriage, including guidebushings affixed to a second upright plate 75 which forms the left-handend of the carriage as it is shown in FIG. 4.

Carriage 72 is constantly urged to the right by coil compression spring76 telescoped over the respective guide rod 74 and acting between theplate 71 and the plate 75, as shown. A laterally centrally locatedmanifold-receiving pocket is provided on the carriage 72, such pocketbeing defined by a laterally central recess 79 in the right-hand face ofplate 75, and two upstanding rods 77 which are secured to the base plate73 of the carriage to the right of recess 79 (FIG. 4). The laterallength of the recess 79 is such as accurately to receive the left-handside portion of a manifold 14 which is placed therein as shown in FIG.4, the rods 77 being spaced from the broad surface of the recess 79 adistance slightly exceeding the width of the manifold 14. The manifoldis thus accurately held on the carriage when the pin-heading operationis performed by the apparatus.

Also supported on the base plate 73 of the carriage 72 is an upstandingrod or post 82 having a horizontal bore therethrough which is coaxial ofthe unheaded pin 52' which has been inserted in the manifold prior tothe mounting of the manifold in the manifold-receiving pocket on thecarriage. Reciprocably mounted in a horizontal passage in the post 82 isa rod 81 having a left-hand end 80 which selectively engages thepreformed head 56 on the pin 52' and backs up the pin while the otherend of the pin is headed. The die rod 81 has an enlarged head 85 on theright-hand end thereof. The die rod 81 is constantly urged toward itsretracted position, shown in FIG. 4, wherein the backup die end 80 ofsuch rod lies just to the right of the right-hand space of the manifold14 mounted in the pocket on the carriage by a coil compression spring 81which acts between the right-hand surface of the post 82 and theleft-hand end surface of the enlargement 85 on the die rod. The coilcompression spring 84 has a compressive resistance which is markedlyless than that exerted by the two coil compression springs 76 actingtogether. The reason for this will become apparent hereafter.

During the operation of heading the pin 52' the enlarged head 85 of thedie rod 81 and thus the die 80 are first thrust to the left to compressspring 81 until the die 80 engages the head 56 of the pin; continuedthrusting of the head 85 to the left carries with it the carriage 72 andthe manifold mounted therein. Such travel of the carriage compresses thesprings 76. Travel of the carriage 72 to the left continues until theleft-hand end of the die plate 96 mounted upon the left side of theplate 75 forming a part of the carriage 72 lies in proximity to theright-hand vertical face of the fixed plate 71. As will be more readilyapparent hereinafter, such travel of the carriage and the manifoldmounted therein to the left is caused by the extension of a piston rod86 attached to a piston within an air cylinder 87, both the piston rodand the air cylinder being disposed to the right of and coaxial of thedie rod 81. Specifically, the air cylinder 87 is mounted at itsleft-hand end upon the upstanding leg portion 89 of an L-shaped bracket,the horizontal lower portion of which is fixedly secured to theright-hand edge portion of the base plate 90 of the apparatus.

An electrically heated die 91, which may be in the nature of an electricsoldering iron powered by a source (not shown) through flexible cable97, has a central cylindrical body 92 and a coaxially disposed tip 94 ofsmaller diameter. The member 91 is disposed coaxial of the die rod 81and the air cylinder 87. The above-mentioned guide plate 96 has apassage 95 therethrough of a diameter such as accurately to receive thetip 94 of the element 91, there being a plurality of radially inwardlydisposed thin members 98 radially arranged around the passage 95 inorder to minimize the loss of heat from the heated tip 94 through theguide member 96 when the tip 94 lies within the passage 95 and thecoaxially arranged passage extending through the plate 75.

The heated die element 92, 94 is constantly reciprocated along itslongitudinal axis. Mounted upon the base plate 70 of the apparatusadjacent the lower left-hand corner thereof, as is shown in FIG. 4,there is an upstanding frame part 99 having a right-hand end laterallyextending portion, a left-hand portion 101 extending laterally in theopposite direction from portion 100, and an intermediate web portion102. A plunger rod 104 is disposed for reciprocation in a horizontalbore in part 100, the plunger 104 having a heat-insulating means 105 bywhich it is connected to the rear or left-hand end of the heated element91. The left-hand end of the plunger rod 102 has an enlarged head 106thereon functioning as a cam follower, the plunger rod 104 beingconstantly urged to the left by a coil compression spring 107 which actsbetween the head 106 and the left-hand vertical surface of the part 100of the frame member 99. A two-lobed cam 109 is fixedly mounted upon theinboard end of a cam shaft 110, the lobes 111 on the cam 109 beingspaced 180° from each other and lying in alignment with the cam followerhead 106 of the plunger 104. The cam shaft and cam are driven by anelectric motor 112 through the medium of a "timing" belt 114 entrainedover a first, smaller motor pulley 115 and a second, larger pulley 116affixed to the outboard end of the cam shaft 110. The motor 112 ispowered by a current source, not shown, the leads from which aredesignated 119; in one of the leads there is interposed a selectivelyoperated switch 117.

Further mechanism for controlling the apparatus is provided as follows:A suitable source of electric power L₁, L₂ is connected to a switch 120which has an operating button 121. Upon depressing the button 121, thelead wires 122 therefrom, which lead to a timer 124, are energized,thereby to accept the timer in operation. The timer has a graduatedscale 125 and a knob having a pointer 126 cooperating therewith, thetimer being able to be preset for a predetermined period, and whenenergized automatically returning to the beginning of a succeedingpredetermined time period of the same length period.

When the lead wires 122 are energized, the timer 124 starts its cycle,and switches on current to wires 129 which lead to an electromagneticswitch 127. Switch 127 is normally closed, but when energized opens toallow the ingress of compressed air through an inlet conduit 130, anormally open shut-off and throttling valve 131, to a flexible conduit132 which leads to an inlet fitting 134 at the rear or right-hand end ofthe air cylinder 87.

The manner of operation of the apparatus of FIG. 4 will become morereadily apparent upon a consideration of the parts a, b and c in FIG. 5.In part a of FIG. 5 a manifold, there designated 14', having an unheadedpin 52' inserted therein, has been placed in the manifold-receivingpocket on the carriage 72, has been engaged by the back-up die 80 on thedie plunger 81, and is being moved to the left with the carriage 72 onwhich it is mounted, by the piston rod 86 of the air cylinder 87. Suchpreliminary position of the manifold 14' is shown in phantom lines atthe right in part a of FIG. 5. After a predetermined length of travel tothe left, the carriage 72 and the manifold 14' thereon are stopped in apredetermined position, wherein the manifold, now designated 14, isshown in full lines in part a of FIG. 5. In such position, the preformedhead 56 of the pin 52' continues to be engaged and backed up by the dieforming head 80 of the die plunger 81.

Meanwhile, the motor 112 has been energized by closing switch 117, andremains constantly in rotation, thereby constantly to reciprocate theheated element 92 and the heated forward end 94 thereof. In theleft-hand portion of parts a of FIG. 5 the element 91 is shown as havingreached the left-hand terminus of its reciprocating travel. In part b ofFIG. 5, the heated element 94 is shown as having been advanced to theright so that the forward end or tip of the heated die 94 has engagedthe previously unheaded part 59 of the pin 52'. Upon the firstengagement between the heated die element 94 and the previously unheadedpart 59 of the pin, part 59 is heated sufficiently to become plastic andto be partially deformed and thrust to the right so as to begin theheading operation.

In such initial contact between the die 94 and the portion 59 of thepin, the carriage 72, the manifold 14, and the pin 52' carried by thelatter are thrust slightly to the right against the opposition affordedby the piston rod 86. Following such initial contact between the die 94and the portion 59 of the pin 52', the die 94 is retracted to the leftso as to pull free of the now partially deformed portion 59 of the pin,permitting it to cool momentarily. Immediately thereafter, the portion59 of the pin is again engaged by the heated die 94. Such operation,that is, the engagement between the portion 59 of the pin and the heateddie 94, followed by the withdrawing of the heated die 94 from engagementwith the pin portion 59 follows until the portion 59 of the pin has beenfully deformed to form a second head on the pin, such operation beingterminated when the preset timer 124 has reached its zero point. In partc of FIG. 5 the heated element 91 and the die tip 94 are shown beingretracted, that is, at a time when the cam follower 106 lies between thetwo cam lobes 111.

After the pin-heading operation has been completed, the timer 124, nowhaving reached zero of its prdetermined time interval, opens the switch120 and closes the electromagnetic valve 127. Thereupon the coilcompression springs 76 thrust the carriage 72 to the right, exhaustingair from the right-hand pin of the air cylinder 87. At the end of thetravel of the carriage 72 to the right, coil compression spring 81 actsto thrust the rod 84 to the right, still further retracting the pistonrod 86, and pulling the back-up die 80 from the cavity within theright-hand side of manifold 14, thereby permitting the manifold with itsnow headed pin 52 to be removed from the pocket on the carriage bypurely vertical movement therefrom. In the portion of part c of FIG. 5the manifold 14 is shown being retracted to the right with the carriage72 (not shown) preparatory to the retraction of the back-up die plunger81.

In accordance with the preferred but non-limiting embodiment of themethod of the invention, the pin 52 is made of an acetal resin such as"Delrin", the melting point of which is about 300-400 degrees F. The pinheading die is heated to a temperature at least 100° F. above themelting of the pin 52. Preferably, the pin heading die 94 is heated to atemperature between 500° and 1000° F. The frequency of reciprocation ofthe heated die 94, that is, the frequency with which it engages the endof the pin being headed and is pulled free therefrom can vary widely.Such frequency of oscillation, may be, for instance, from three or fourtimes per second up to as much as 20 or more times per second. All ofthe above parameters can, of course, vary depending upon the nature ofthe material from which the pin is made, the size of the pin, and themaximum time in which the heated die can safely be left in contact withthe end of the pin being headed, at each such engagement therebetween,without causing sticking between the die and the pin. In one manner ofcarrying out the instant invention, that is, the heading of "Delrin"pins in a manifold as above-described, the frequency of reciprocation ofthe heated die lies between three to four per second. The optimumparameters result in the production of a satisfactory head on the pin,without the sticking of the die to the pin, in the shortest possibletime.

It has been found that employment of the method and apparatus of theinvention results in a 50-80 percent saving in labor time, that is, theassembly of the pin in the manifold and its heading takes but 20-50percent of the time which was formerly necessary to thread the copperwire through the body of the manifold and the operating lever, to tie asquare knot in such wire, and to sever the wire from the wire supplied.

It is to be understood in the above description of the apparatus of theinvention and its manner of functioning that the back-up die 80 comes toa stop in its travel to the left when the coil compression spring 84 issqueezed tight between post 82 and member 85. It is also to beunderstood that reciprocable fluid motor 87 is subjected to fluid undersuch pressure that piston rod 86 is yieldable, that is, the pin beingheaded and the back-up die 80 can move to the right when necessary asheading die 92 approaches and reaches its position of maximum extensionto the right.

Although the invention is illustrated and described with reference to asingle preferred embodiment thereof, it is to be expressly understoodthat it is in no way limited to the disclosure of such a preferredembodiment, but is capable of numerous modifications within the scope ofthe appended claims.

What is claimed is:
 1. A method of forming by a heated die a head on an end of a pin made of a thermoplastic acetal resin, comprising heating the die to a temperature substantially above the melting point of the pin, reciprocating the die toward and away from the end of the pin to be headed so as repeatedly briefly compressively to engage the pin and progressively to deform it to form a head thereon, and after each such engagement between the die and the pin removing the die from engagement with the pin before sticking occurs between them, the partially deformed portion of the pin cooling momentarily when the die is removed from engagement therewith.
 2. A method according to claim 1, wherein the heated die reciprocates alternately to engage the pin being headed and to withdraw from engagement therewith with a frequency of from 3 to 20 times a second.
 3. A method according to claim 2, wherein the pin heading die is heated to a temperature at least 100° F. above the melting point of the pin.
 4. A method according to claim 3, wherein the pin has a melting point of about 300°-400° F., and the pin heading die is heated to a temperature between 500° and 1000° F.
 5. A method of heading a thermoplastic pin inserted in a passage in a body, comprising supporting the body with the pin inserted therein with a first, unheaded end of the pin protruding from a first side of the body, heating a pin heading die above the melting point of the pin, mounting the die axially of the pin and confronting the first end of the pin, and reciprocating the heading die in the body and the pin inserted therein relatively toward and away from each other at a frequency of from 3 to 20 times a second so that the die alternately engages the first end of the pin and is withdrawn from engagement therewith, whereby the first end of the pin is repeatedly partially melted and compressed so that a head is progressively formed on said first end of the pin, the partially deformed portion of the pin cooling momentarily when the die is withdrawn from engagement therewith.
 6. A method according to claim 5, wherein the means for supporting the body is a carriage having a body supporting means thereon, and comprising continuously reciprocating the die between the retracted position and an extended position, and thrusting the carriage toward the die so that the first end of the pin is engaged by the die when the latter is in its extended position but is out of engagement with the die when the latter is in its retracted position.
 7. A method according to claim 6, wherein the thrusting of the carriage toward the die is yieldable, and comprising stopping the carriage in an advanced terminal position nearest the heading die.
 8. A method according to claim 5, wherein the thermoplastic material is an acetal resin, and the withdrawing of the die from engagement with the pin takes place before the plastic material sticks to the die. 